create ability to initialize 3d simulation from 2d axisymmetric

[zingale]

It would be great to have the ability to take a 2d axisymmetric simulation and use it to initialize a 3d calculation by rotating it about the vertical axis. This can be a nice way to start a simulation in 2d and once it evolves enough, transfer it to 3d.

[zingale]

the Maestro to Castro code uses a plotfile to initialize, but I am not sure if we can leverage this if the plotfile is 2d but our simulation is 3d.

[zingale]

Weiqun made changes to AMReX that should allow this. His example:

#include <AMReX.H>
#include <AMReX_Print.H>
#include <AMReX_VisMF.H>
#include <AMReX_MultiFab.H>
​
using namespace amrex;
​
int main(int argc, char* argv[])
{
    amrex::Initialize(argc,argv);
    {
        std::string file_name{"Dust-2d-P_plt00020"};
​
        // read header
        std::string header_file_name = file_name+"/Header";
        Vector<char> filechar;
        ParallelDescriptor::ReadAndBcastFile(header_file_name, filechar);
        std::string header_file_string{filechar.data()};
        std::istringstream is(header_file_string, std::istringstream::in);
​
        std::string line;
        std::getline(is, line);
        amrex::Print() << "Plotfile Type: " << line << "\n";
​
        int nvars;
        is >> nvars;
        amrex::Print() << "# of variables: " << nvars << "\n";
​
        Vector<std::string> var_names(nvars);
        for (auto& vn : var_names) {
            is >> vn;
            amrex::Print() << "    " << vn << "\n";
        }
​
        int plotfile_spacedim;
        is >> plotfile_spacedim;
        amrex::Print() << "Space Dimension: " << plotfile_spacedim << "\n";
​
        Real t;
        is >> t;
        amrex::Print() << "Time: " << t << "\n";
​
        int flev;
        is >> flev;
        amrex::Print() << "Finest Level: " << flev << "\n";
​
        Vector<Real> problo(plotfile_spacedim);
        amrex::Print() << " Problo:";
        for (int i = 0; i < plotfile_spacedim; ++i) {
            is >> problo[i];
            amrex::Print() << " " << problo[i];
        }
        amrex::Print() << "\n";
​
        Vector<Real> probhi(plotfile_spacedim);
        amrex::Print() << " Probhi:";
        for (int i = 0; i < plotfile_spacedim; ++i) {
            is >> probhi[i];
            amrex::Print() << " " << probhi[i];
        }
        amrex::Print() << "\n";
​
        Vector<int> ref_ratio(flev);
        if (flev > 0) {
            amrex::Print() << "Refinement Ratio:";
            for (int lev = 0; lev < flev; ++lev) {
                is >> ref_ratio[lev];
                amrex::Print() << " " << ref_ratio[lev];
            }
            amrex::Print() << "\n";
        }
​
        Vector<Box> domain(flev+1);
        amrex::Print() << "Domain Box:\n";
        for (auto& d : domain) {
            is >> d;
            amrex::Print() << "    " << d << "\n";
        }
​
        Vector<int> level_steps(flev+1);
        amrex::Print() << "Level Steps:\n";
        for (auto& ls : level_steps) {
            is >> ls;
            amrex::Print() << "    " << ls << "\n";
        }
​
        Vector<Array<Real,AMREX_SPACEDIM> > cell_size(flev+1,{AMREX_D_DECL(1.,1.,1.)});
        for (int lev = 0; lev <= flev; ++lev) {
            amrex::Print() << "Cell Size on Level " << lev << ":";
            for (int i = 0; i < plotfile_spacedim; ++i) {
                is >> cell_size[lev][i];
                amrex::Print() << " " << cell_size[lev][i];
            }
            amrex::Print() << "\n";
        }
​
        int coord;
        is >> coord;
        amrex::Print() << "Coordinate Type: " << coord << "\n";
​
        int bndry_data;
        is >> bndry_data;
​
        // ... there are more data in Header...
​
        Vector<MultiFab> plotfile_data(flev+1);
        for (int lev = 0; lev <= flev; ++lev) {
            std::string mf_file_string = file_name + "/Level_"+std::to_string(lev)+"/Cell";
            VisMF::Read(plotfile_data[lev], mf_file_string);
            amrex::Print() << "Level " << std::to_string(lev) << " Plotfile_data BoxArray: "
                           << plotfile_data[lev].boxArray();
            const int ncomp = plotfile_data[lev].nComp();
            for (int icomp = 0; icomp < ncomp; ++icomp) {
                amrex::Print() << "    Component " << icomp << " min and max = "
                               << plotfile_data[lev].min(icomp) << ", "
                               << plotfile_data[lev].max(icomp) << "\n";
            }
        }
    }
    amrex::Finalize();
}

[zingale]

if we read in a multilevel 2d plotfile, we need to somehow already have a multilevel 3d MF that matches the gridding, so there is data everywhere we need to map.

[KiranEiden]

Andrew and I were thinking we could do the following:

• Load the 2d data into a 3d MultiFab (and the other information into fake versions of the Amr, AmrLevel, and StateData classes)
• Create a second 3d MultiFab to store the 3d data
• Distribute particles in the MultiFab with the uninitialized 3d data (one to each grid cell)
• Transform the particles into 2d axisymmetric coords, and redistribute them in the 2d MultiFab
• Sample from the 2d data using the particles (using them like tracer particles)
• Transform back into 3d Cartesian, and redistribute them again in the 3d MultiFab
• Initialize each cell with the data sampled by its particle